The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
With the development of the network technology, and the appearance of massive mobile terminals, such as laptops, personal digital assistants (PDA), mobile phones, and car devices, more and more users can connect to the Internet through the public mobile wireless network at any site by using various terminals. To meet the requirement of the mobile services, the mobile Internet protocol (IP) is imported to the network layer.
The basic principle of the mobile IP is allowing a mobile node to use an original IP address for IP communication while moving, thus ensuring non-interruption and continuity of the upper layer applications carried by the IP network during the moving procedure.
With the expansion of network scale, the Internet Protocol version 6 (IPv6) technology will gradually replace the current Internet Protocol version 6 (IPv4) technology because of the advantage of large address space. The IPv6-based mobile IP, namely, mobile IPv6 technology, depends on the technology advantages of the IPv6 and the improvement on mobile IPv4, and becomes popular in the mobile IP domain, which is more and more widely used.
FIG. 1 shows the basic principle of the mobile IPv6. Referring to FIG. 1. When a mobile node 111 connects to a home network 110, it adopts the same working mode as that of a fixed node. The mobile node 111 detects whether it roams to a foreign network by using the IPv6 neighbor discovery system. A gateway of the IPv6 network periodically sends a router advertisement message which comprises a home network prefix of the gateway. When the mobile node receives the router advertisement message from the gateway, it considers that it has roamed to a foreign network if it finds that the network prefix comprised is different from that of the home network. If the mobile node 111 finds that it has roamed to a foreign network 120, it obtains the care-of address on the foreign network 120 through the address auto configuration with or without the status based on the received router advertisement message. At this time, the mobile node 111 has the home address and the care-of address at one time. Currently, the mobile node 111 and a correspondent partner 130 communicate with each other mainly in two modes.
Mode I can be called as a triangle routing mode. The mobile node 111 registers the care-of address to a home agent 113 through a binding update message. A message sent to the correspondent partner 130 is firstly sent to the home agent 113 by the mobile node 111 through a reverse tunnel, and then forwarded to the correspondent partner 130 by the home agent 113. The correspondent partner 130 of the mobile node 111 sends data packets to the home network 110 of the mobile node according to the home address of the mobile node. Then the home agent 113 will intercept these data packets, and forward these data packets to the mobile node 111 by using a tunnel mechanism based on the current care-of address of the mobile node. That is to say, in this mode, the data packets between the correspondence partner 130 and the mobile node 111 are transferred by the home agent 113.
Mode II can be called as a routing optimization mode. The mobile node 111 registers the care-of address to the correspondence partner 130 through a binding update message. Before the registration, a return routability test process is first carried out between the mobile node 111 and the correspondence partner 130, that is, the mobile node 111 first sends a Home Init Test message and a Care-of Init Test message to the correspondence partner 130. After processing, the correspondence partner 130 returns a Home Test message and a Care-of Test message to the mobile node 111. A source address of a data packet sent by the mobile node 111 to the correspondence partner 130 is the care-of address, while the home address is saved in a destination expansion header of the data packet. Therefore, the data packet can be directly sent to the correspondence partner 130 without being sent to the home agent 113 through the reverse tunnel. If the correspondence partner 130 learns the care-of address of the mobile node through the binding update message, it will use an IPv6 route header to send a data packet directly to the mobile node 111. The first destination address of the data packet is the care-of address, and the second one is the home address. Therefore, the data packet can be sent directly to the mobile node 111 in the foreign network, without transfer by the home agent 113. That is to say, in this routing mode, the service packet is directly transmitted between the mobile node 111 and the correspondence partner 130.
The current two communication modes of the mobile IP have some disadvantages.
In the triangle routing mode, the transmission of the service packet must pass through the home agent. In certain extreme case, if the mobile node is adjacent to a correspondence node (correspondence partner) or the two nodes locate in the same subnet and they are far away from the home agent, the service packet must round a long distance to reach the other party. In this case, the service that essentially could be sent with low cost requires more charge, which may lead to unnecessary time delay, jitter, and packet loss.
The routing optimization mode addresses various concerns with the triangle routing mode. But the care-of address of the mobile node is revealed to the correspondence node. In this way, the correspondence node can obtain the current location of the mobile node by using certain mode and tool, thus uncovering the location of the mobile node. That is to say, it's not ensured that the care-of address can be obtained only by the trusty third party or the correspondence node.